Also on Wednesday, Van Eck Associates Corp pulled a registration document for a bitcoin fund after saying the SEC told them they would not review the filing until futures contracts on the digital currency start trading.

“Although digital currency market regulation continues to rapidly evolve, at this time Grayscale does not believe there have been enough regulatory developments to prompt the SEC to approve the ... application,” Grayscale said in a statement. They said they would continue their dialogue with regulators.

The Bitcoin Investment Trust is currently traded “over the counter” in less formal exchanges than those used for typical stocks and at far higher prices than the bitcoin it holds.

Shares traded down 3.2 percent to $715.50 on Thursday, far higher than the issuer’s appraisal that its bitcoin assets are worth $386.60 per share.

GBTC shares gained nearly 500 percent this year, more even than the 332 percent rise of bitcoin BTC=BTSP to more than $4,100.

Bitcoin can be used to move money with relative anonymity, and without the need for a central authority, such as a bank or government.

SEC approval could bring more investors to the asset, yet the regulatory agency has expressed doubts over the bitcoin market being unregulated. The SEC declined to comment. NYSE could not be reached.

In March, the SEC blocked two potential bitcoin products, including one backed by Cameron and Tyler Winklevoss, twin investors best known for feuding with Facebook Inc (FB.O) founder Mark Zuckerberg. CBOE Holdings Inc’s CBOE.O Bats exchange, which wanted to host that exchange-traded fund, appealed the ruling.

A proposal to list a product based on ether, another digital currency, was pulled earlier this month.

Bitcoin-tracking products already trade in Europe and one is being considered in Canada.

Regulators have not weighed in on two other efforts to bring a digital currency to U.S. exchanges, including a proposal filed on Wednesday by ProShare Capital Management LLC for a fund that would short bitcoin futures, betting their prices will fall.

Reporting by Trevor Hunnicutt in New York; Additional reporting by Kanishka Singh in Bengaluru; editing by Alexander Smith and Lisa Shumaker